android / platform / external / chromium_org / third_party / skia / src / eb8698b / . / core / SkMatrixUtils.h

/* | |

* Copyright 2013 Google Inc. | |

* | |

* Use of this source code is governed by a BSD-style license that can be | |

* found in the LICENSE file. | |

*/ | |

#ifndef SkMatrixUtils_DEFINED | |

#define SkMatrixUtils_DEFINED | |

#include "SkMatrix.h" | |

/** | |

* Number of subpixel bits used in skia's bilerp. | |

* See SkBitmapProcState_procs.h and SkBitmapProcState_filter.h | |

*/ | |

#define kSkSubPixelBitsForBilerp 4 | |

/** | |

* Given a matrix and width/height, return true if the computed dst-rect would | |

* align such that there is a 1-to-1 coorspondence between src and dst pixels. | |

* This can be called by drawing code to see if drawBitmap can be turned into | |

* drawSprite (which is faster). | |

* | |

* The src-rect is defined to be { 0, 0, width, height } | |

* | |

* The "closeness" test is based on the subpixelBits parameter. Pass 0 for | |

* round-to-nearest behavior (e.g. nearest neighbor sampling). Pass the number | |

* of subpixel-bits to simulate filtering. | |

*/ | |

bool SkTreatAsSprite(const SkMatrix&, int width, int height, | |

unsigned subpixelBits); | |

/** | |

* Calls SkTreatAsSprite() with default subpixelBits value to match Skia's | |

* filter-bitmap implementation (i.e. kSkSubPixelBitsForBilerp). | |

*/ | |

static inline bool SkTreatAsSpriteFilter(const SkMatrix& matrix, | |

int width, int height) { | |

return SkTreatAsSprite(matrix, width, height, kSkSubPixelBitsForBilerp); | |

} | |

/** Decomposes the upper-left 2x2 of the matrix into a rotation (represented by | |

the cosine and sine of the rotation angle), followed by a non-uniform scale, | |

followed by another rotation. If there is a reflection, one of the scale | |

factors will be negative. | |

Returns true if successful. Returns false if the matrix is degenerate. | |

*/ | |

bool SkDecomposeUpper2x2(const SkMatrix& matrix, | |

SkPoint* rotation1, | |

SkPoint* scale, | |

SkPoint* rotation2); | |

#endif |